The evolution and characterisation of the corrosion scales formed on 3Cr steel in CO2-containing conditions relevant to geothermal energy production

The corrosion behaviour of 3Cr steel at CO2 partial pressures (pCO2) 2.7/28.5 bar and 200 °C was investigated. evolution double-layered scales analysed by surface analysis to identify physical chemical nature results are combined with an thermodynamic calculations. Both experimental show that the comprise a crystalline FeCO3 outer layer inner Fe3O4, FeCr2O4, Cr(OH)3 2.7 pCO2. At 28.5 pCO2, evolves be mixture FeCr2O4 containing concentrated Cl? ions, this induces enhancement localised corrosion.